The invention relates to a device for generating a liquid detergent concentrate from a solid detergent, a method for generating a liquid detergent concentrate from a solid detergent, and to a method for washing a vehicle.
Liquid detergent concentrates for use in the vehicle washing industry are conventionally shipped in large containers. Typically, a line is attached to the container containing the large amount of liquid detergent concentrate, and a portion of the liquid detergent concentrate is drawn off for each vehicle washing cycle. Shipping large concentrates of liquid detergent can be expensive. In addition, disposal of the container that holds the liquid detergent concentrate can be problematic.
As an alternative to shipping large volumes of liquid concentrate, large volumes of liquid concentrate can be generated on site by mixing a detergent powder with water. Once the liquid concentrate is used up, a new batch of liquid concentrate can be prepared. One technique for preparing a liquid concentrate from detergent powder is by submerging the detergent powder in a tank filled with an aqueous solution. This technique requires an operator to place detergent directly into standing water. Splashing caused by adding the detergent directly into the concentrated solution and/or mechanical mixing using a mixing blade can pose a safety hazard.
Much attention has been directed by Ecolab Inc., the assignee of this patent application, in preparing liquid detergents from solid detergent concentrates. This focus of attention has been directed mostly at warewashing and clothes washing. See, for example, U.S. Pat. No. 4,687,121 issued to Copeland et al; and U.S. Pat. Nos. 4,569,781 and 4,569,780 issued to Fernholz et al.
A device for generating a liquid detergent concentrate from a solid detergent is provided according to the invention. The device includes a solid detergent reservoir, a water inlet, a stock solution reservoir, and a hot water heater. The solid detergent reservoir is provided for holding solid detergent, and includes a stock solution generating region for generating stock solution from solid detergent provided within the solid detergent reservoir. The water inlet is provided for directing water onto solid detergent provided within the solid detergent solution generating region of the solid detergent reservoir for generating stock solution. The stock solution reservoir is provided for holding stock solution generated in the stock solution generating region. The stock solution reservoir includes a stock solution inlet for receiving stock solution from the stock solution generating region, a stock solution outlet for removal of stock solution from the stock solution reservoir, and a stock solution level sensor for sensing the level of stock solution provided within the stock solution reservoir and for generating a first signal and a second signal. The first signal indicates when the stock solution reservoir requires additional stock solution, and the second signal indicates when the stock solution reservoir has a sufficient amount of stock solution. The hot water heater is provided for controlling the temperature of water provided to the water inlet.
A method for generating a liquid detergent concentrate from a solid detergent is provided according to the invention. The method includes steps of: (a) applying water against a solid detergent in a solid detergent reservoir to provide a liquid detergent concentrate, wherein the water is provided at a relatively constant temperature and the relatively constant temperature is provided within a range of about 40xc2x0 F. and about 150xc2x0 F.; (b) collecting the liquid detergent concentrate in a liquid detergent concentrate reservoir; (c) monitoring the amount of liquid detergent concentrate within the liquid detergent concentrate reservoir and providing a first signal and a second signal, the first signal indicating when sufficient liquid detergent concentrate is provided within the liquid detergent concentrate reservoir and the second signal indicating when more liquid detergent concentrate is needed within the liquid detergent concentrate reservoir; and (d) controlling the flow of water against the solid detergent provided within the solid detergent reservoir based on the first signal and the second signal.
A method for washing a vehicle is provided according to the invention. The method includes steps of: (a) applying water against a solid detergent provided within a solid detergent reservoir to generate a liquid detergent concentrate; (b) collecting the liquid detergent concentrate in a liquid detergent concentrate reservoir; (c) withdrawing liquid detergent concentrate from the liquid detergent concentrate reservoir and combining the liquid detergent concentrate with water to provide a use solution; and (d) washing the vehicle with the use solution.